In UFC fight, mixed martial arts and brain science collide

(CNN) -- So, the Packers won the Super Bowl, but fans of mixed martial arts can't stop talking about how Anderson Silva took down Vitor Belfort in an Ultimate Fighting Championship title match with a single kick.

The Brazilian fighters started off relatively lightly, circling each other for the first minute of Saturday night's bout. Belfort briefly took Silva down, but the UFC middleweight champion bounced right back up. Suddenly, Silva threw a left front kick to the jaw that knocked Belfort to the mat, and then threw a couple of punches that seemed almost unnecessary to end the match against the dazed fighter.

The highly anticipated fight lasted less than 3½ minutes.

Belfort, saying he is "doing great," spoke with CNN after attending his 6-year-old son's birthday party in Las Vegas, Nevada, and talked about the blow he described as "one kick in a million."

"Your brain kind of slows down," he said. "The kick landed pretty hard, but this type of kick, it's more like a pushing kick right under my chin, it took me right out of my balance," he said.

Fighting experts say it's uncommon for a front kick to have so much impact. After the fight, Silva credited action-movie actor Steven Seagal with helping him perfect the move.

Belfort says he never lost consciousness, but "for a split second, I was a little bit out," and the fight was stopped because he couldn't defend himself once on the ground. Unlike boxing, where participants are given to the count of 10 to recover, UFC matches are ended on a "technical knockout" as soon as a fighter cannot defend himself.

Repeated blows to the head may cause severe brain injury, especially over time. Once a player has been hit once as Belfort was, additional trauma soon after could have had a worse impact, resulting in loss of consciousness.

And even though Belfort felt ready for revenge seconds after Silva was declared the winner -- "I even told them, 'Why do you stop the fight?'" -- he said he respects that UFC rules are designed to protect him from serious damage. "You already have like a bruise on your brain," the fighter said.

Former football players, fighters and boxers alike report cognitive deficits such as Alzheimer's symptoms that may have resulted from such brain damage suffered over and over during long careers. A new vision test may be able to detect whether a concussion has occurred.

Knockouts happen because the brain isn't completely glued to the skull; it has room for movement. A kick or punch to the jaw can displace it, said Dr. Osric King, sports medicine physician at Hospital for Special Surgery in New York, and Medical Advisor for the New York State Athletic Commission.

For the most part, the brain is secured by blood vessels and nerves that are integrated between the skull and different layers of tissue, he said. When the jaw is kicked with enough force, the brain and nerves reach a critical point where they can't sustain consciousness. As the blood vessels get stretched out, they're not able to sustain the continued blood supply the brain may need, and the person may black out immediately.

Concussions don't necessarily involve loss of consciousness; in fact, most don't, and it's possible to have a concussion without realizing it, according to the Mayo Clinic. Symptoms may include loss of balance and confusion, as well as headache and difficulty sleeping.

Doctors examined Belfort afterward and found nothing wrong, the fighter said, and today he has no headache or jaw problems.

The area of the jaw that Silva hit is very vulnerable, and a target every fighter will aim for, but there's not a lot of science behind why this is a sweet spot. Conducting an experiment on knocking people out in particular ways would be unethical, of course, King said.

There's no hard science on a recovery period, but athletic organizations follow rough guidelines in accordance with the severity of the injury, King said. After a single knockout involving loss of consciousness, there needs to be a healing process of at least about 60 to 90 days before coming back to fighting, King said. In boxing, a technical knockout usually requires 45 days off. If a fighter goes back in too quickly, he'll be more susceptible to getting knocked out even more easily, he said.

Belfort wishes he could fight again right now, but the Nevada Athletic Commission has recommended Belfort take a month off and refrain from any activity that may cause additional trauma. He said he'll take a break for two weeks and then do some physical training at the gym. The amount of time a fighter should take off after a knockout depends on his condition, as determined by the athletic commission.

Some people are a little more prone than others to getting knocked out, or don't recover as well, King said. Some fighters are said to have a "good chin" -- they are better at enduring blows. In those individuals, the brain may have adapted to that kind of injury, or the cumulative damage isn't as obvious as it is in others, King said.

"There are some people who can take that shot over and over again, but there is a point of no return, too," said Javier Mendez, a mixed martial arts trainer for more than 30 years, who also worked with retired NFL star Herschel Walker.

If you're expecting a blow like that, you can prepare yourself by tightening neck muscles and attempt to deflect it, King said.

But Belfort was caught off guard.

He said he feels fine physically, and "the only thing that's really bothering me is that one kick in a million that hit me."

"I know in my heart I did the best I could," Belfort said. "That's the beauty of the fight: Anything can happen."